Bis-triarylamine compound and organic electroluminescent device

Abstract

The invention relates to the field of preparation of organic light-emitting diodes, in particular to a bis-triarylamine compound and an organic electroluminescent device. Wherein the bis-triarylamine compound has a structure as shown in a formula (a). The device adopting the compound provided by the invention has long service life and high efficiency.

Description

Technical Field

[0001] This invention relates to the field of organic light-emitting diode (OLED) fabrication, and in particular to a bis(triarylamine) compound and an organic electroluminescent device. Background Technology

[0002] OLED, or Organic Light Emitting Diode, has advantages such as high brightness, high contrast, and the ability to design transparent displays, while also having low production costs.

[0003] The working principle of OLED devices is as follows: When a voltage is applied to an organic light-emitting device, holes and electrons are injected from the anode and cathode, respectively, and recombine in the light-emitting layer to form excitons. When these excitons recover from a higher-energy, unstable excited state to a lower-energy, stable ground state, energy is released in the form of photons, and the device emits light. The materials of the auxiliary layers in an OLED device also have a significant impact on the device's efficiency and lifetime.

[0004] In existing technologies, the main purpose of adding an electron blocking layer is twofold: firstly, to block unrecombined electrons in the emissive layer and to transfer holes to the emissive layer; and secondly, to adjust the optical microcavity of the device by designing the thickness of this layer. These two aspects primarily improve the luminous efficiency of the device. However, the electron blocking layer is also susceptible to attack from high-energy excitons in the emissive layer. Therefore, to obtain OLED devices with long lifespans, the electron blocking layer material needs to have a strong ability to resist excitons.

[0005] Bistriarylamine compounds possess excellent hole transport and electron blocking properties, and are widely used in auxiliary layers, such as hole transport layers or electron blocking layers. However, the lifespan and efficiency of these devices still need further improvement. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a bis(triarylamine) compound and an organic electroluminescent device. Devices using the compounds provided by this invention have high lifespan and efficiency.

[0007] This invention provides a bis(triarylamine) compound having the structure shown in formula (a):

[0008]

[0009] in,

[0010] Ar1 to Ar4 may be the same as or different from each other, and each is independently selected from aryl groups with 6 to 22 substituted or unsubstituted carbon atoms and heteroaryl groups with 3 to 30 substituted or unsubstituted carbon atoms, and satisfies the condition that at least one of Ar1 to Ar4 is selected from the group described in formula (b1), and at least one is selected from the group described in formula (b2).

[0011]

[0012] m, n, r are each independently selected from integers between 0 and 4;

[0013] p and q are each independently selected from integers between 0 and 7;

[0014] Each of R1 to R5 may be the same or different from each other, and each is independently selected from deuterium, phenyl, or naphthyl.

[0015] The present invention also provides a functional layer comprising the aforementioned bis(triarylamine) compounds.

[0016] The present invention also provides the use of the aforementioned bis(triarylamine) compounds and / or the aforementioned functional layers in organic electroluminescent devices.

[0017] The present invention also provides an organic electroluminescent device, comprising a first electrode, a second electrode, and a functional layer as described above, wherein the functional layer is at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron injection layer, or an electron transport layer.

[0018] The present invention also provides a display or lighting device comprising an organic electroluminescent device as described above.

[0019] By adopting the aforementioned technical solution, the beneficial effects of the present invention are:

[0020] This invention is applied to the electron blocking layer of blue organic electroluminescent devices, and compared with the comparative compounds, the performance indicators of the devices are improved to varying degrees.

[0021] This invention uses a diphenyl group as the parent nucleus, with an arylamine group introduced at the 4-position (para-position) of the diphenyl group to ensure good hole transport properties. Furthermore, another arylamine group is introduced at the 2'-position (meta-position) of the diphenyl group, further enhancing the hole transport properties while also increasing the steric hindrance effect to some extent. On the one hand, the molecule tends to form a uniform, amorphous film during vacuum deposition, and even under conditions of high Joule heating during long-term device operation, the film is less prone to phase transition, thus improving device stability. On the other hand, the molecule has a high singlet energy level, which can resist high-energy excitons from the light-emitting layer, resulting in high device efficiency. Moreover, when at least one of the "aryl" groups in the arylamine group is selected from a naphthyl group bonded to the para-position of a phenyl group, this aryl combination not only has extended conjugation, but the terminal naphthyl group also provides a larger conjugated plane and electron-withdrawing effect. This not only further enhances the hole migration properties of molecules, but more importantly, when the molecule is attacked by electrons from the luminescent layer and becomes negatively charged, the extended conjugation can effectively separate the domain charge, thus improving the stability of the molecule in the negatively charged state. This is highly beneficial for the application of electron blocking layer materials. When at least one of the "aryl" groups in the arylamine group is selected from naphthyl groups, it works synergistically with the naphthyl group bonded to the para-position of the aforementioned phenyl group to extend the molecular conjugation and improve the stability of the molecule in the negatively charged state. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the organic electroluminescent device in the embodiment of the blue light device.

[0023] In the picture:

[0024] 101 base

[0025] 102 First Electrode

[0026] 103 Hole Injection Layer

[0027] 104 Hole Transport Layer

[0028] 105 Electron Blocking Layer

[0029] 106 Emissive Layer

[0030] 107 Hole-blocking layer

[0031] 108 Electron Transport Layer

[0032] 109 Second Electrode

[0033] 110 Covering Layer Detailed Implementation

[0034] The following details the embodiments of the bis(triarylamine) compounds and organic electroluminescent devices provided by the present invention.

[0035] The inventors of this proposal made a surprising discovery that compounds with a specific structure have a long service life, thus completing this invention.

[0036] This application will be described in detail below. However, the following description is intended to explain the invention and is not intended to limit the scope of the invention in any way.

[0037] In this application, the term "aryl" refers to a monocyclic or fused-ring group derived from an aromatic hydrocarbon having a cyclic skeleton carbon atom, wherein the number of cyclic skeleton carbon atoms is preferably 6 to 22, 6 to 18, 6 to 15, more preferably 6 to 12, and may be partially saturated and may contain a spirostructure. Specific examples of aryl groups include phenyl, biphenyl, terphenyl, tetraphenyl, naphthyl, binatyl, phenylnaphthyl, naphthylphenyl, fluorenyl, phenylfluorenyl, dimethylfluorenyl, diphenylfluorenyl, benzo[fluorenyl], diphenylbenzo[fluorenyl], dibenzo[fluorenyl], phenanthrene, benzo[phenanthrene], phenylphenanthrene, anthracene, benzo[anthrene], indole, triphenylene, pyrene, tetraphenyl, peryl, benzo[fluorenyl], naphthyl, fluoranthyl, benzo[fluorenyl], tolyl, xylyl, trimethylyl, cumene, spiro[fluorenyl-fluorenyl], spiro[fluorenyl-benzo[fluorenyl]], azulel, tetramethyl-dihydrophenanthrene, etc. More specifically, the aryl group can be o-tolyl, m-tolyl, p-tolyl, 2,3-xylyl, 3,4-xylyl, 2,5-xylyl, mesitylene, o-cumenyl, m-cumenyl, p-cumenyl, p-tert-butylphenyl, p-(2-phenylpropyl)phenyl, 4'-methylbiphenyl, 4'-tert-butyl-p-terphenyl-4-yl, o-biphenyl, m-biphenyl, p-biphenyl, o-terphenyl, m-terphenyl-4-yl, m-terphenyl-3-yl, m-terphenyl-3-yl Biphenyl-2-yl, p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, m-tetraphenyl, 1-naphthyl, 2-naphthyl, 1-fluorenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl, 9-fluorenyl, 9,9-dimethyl-1-fluorenyl, 9,9-dimethyl-2-fluorenyl, 9,9-dimethyl-3-fluorenyl, 9,9-dimethyl-4-fluorenyl, 9,9-diphenyl-1-fluorenyl, 9,9-diphenyl-2-fluorenyl, 9,9-diphenyl-3-fluorenyl, 9,9-di Phenyl-4-fluorenyl, 1-anthrayl, 2-anthrayl, 9-anthrayl, 1-phenanthyl, 2-phenanthyl, 3-phenanthyl, 4-phenanthyl, 9-phenanthyl, 1-yl, 2-yl, 3-yl, 4-yl, 5-yl, 6-yl, benzo[c]phenanthyl, benzo[g]yl, 1-triphenylene, 2-triphenylene, 3-triphenylene, 4-triphenylene, 3-fluoranthyl, 4-fluoranthyl, 8-fluoranthyl, 9-fluoranthyl, benzo[fluoranthyl]fluoranthyl, 11,11-dimethyl-1-benzo[a]fluorenyl, 11,11-dimethyl -2-benzo[a]fluorenyl, 11,11-dimethyl-3-benzo[a]fluorenyl, 11,11-dimethyl-4-benzo[a]fluorenyl, 11,11-dimethyl-5-benzo[a]fluorenyl, 11,11-dimethyl-6-benzo[a]fluorenyl, 11,11-dimethyl-7-benzo[a]fluorenyl, 11,11-dimethyl-8-benzo[a]fluorenyl, 11,11-dimethyl-9-benzo[a]fluorenyl, 11,11-dimethyl-10-benzo[a]fluorenyl, 11,11-Dimethyl-1-benzo[b]fluorenyl, 11,11-dimethyl-2-benzo[b]fluorenyl, 11,11-dimethyl-3-benzo[b]fluorenyl, 11,11-dimethyl-4-benzo[b]fluorenyl, 11,11-dimethyl-5-benzo[b]fluorenyl, 11,11-dimethyl-6-benzo[b]fluorenyl, 11,11- Dimethyl-7-benzo[b]fluorenyl, 11,11-dimethyl-8-benzo[b]fluorenyl, 11,11-dimethyl-9-benzo[b]fluorenyl, 11,11-dimethyl-10-benzo[b]fluorenyl, 11,11-dimethyl-1-benzo[c]fluorenyl, 11,11-dimethyl-2-benzo[c]fluorenyl, 11,11-dimethyl 11,11-Dimethyl-4-benzo[c]fluorenyl, 11,11-Dimethyl-5-benzo[c]fluorenyl, 11,11-Dimethyl-6-benzo[c]fluorenyl, 11,11-Dimethyl-7-benzo[c]fluorenyl, 11,11-Dimethyl-8-benzo[c]fluorenyl, 11,11-Dimethyl-9 -Benzo[c]fluorenyl, 11,11-dimethyl-10-benzo[c]fluorenyl, 11,11-diphenyl-1-benzo[a]fluorenyl, 11,11-diphenyl-2-benzo[a]fluorenyl, 11,11-diphenyl-3-benzo[a]fluorenyl, 11,11-diphenyl-4-benzo[a]fluorenyl, 11,11-diphenyl-5-benzyl [a]fluorenyl, 11,11-diphenyl-6-benzo[a]fluorenyl, 11,11-diphenyl-7-benzo[a]fluorenyl, 11,11-diphenyl-8-benzo[a]fluorenyl, 11,11-diphenyl-9-benzo[a]fluorenyl, 11,11-diphenyl-10-benzo[a]fluorenyl, 11,11-diphenyl-1-benzo[a]fluorenyl [b]fluorenyl, 11,11-diphenyl-2-benzo[b]fluorenyl, 11,11-diphenyl-3-benzo[b]fluorenyl, 11,11-diphenyl-4-benzo[b]fluorenyl, 11,11-diphenyl-5-benzo[b]fluorenyl, 11,11-diphenyl-6-benzo[b]fluorenyl, 11,11-diphenyl-7-benzo[b]fluorenyl 11,11-diphenyl-8-benzo[b]fluorenyl, 11,11-diphenyl-9-benzo[b]fluorenyl, 11,11-diphenyl-10-benzo[b]fluorenyl, 11,11-diphenyl-1-benzo[c]fluorenyl, 11,11-diphenyl-2-benzo[c]fluorenyl, 11,11-diphenyl-3-benzo[c]fluorenyl 11,11-Diphenyl-4-benzo[c]fluorenyl, 11,11-Diphenyl-5-benzo[c]fluorenyl, 11,11-Diphenyl-6-benzo[c]fluorenyl, 11,11-Diphenyl-7-benzo[c]fluorenyl, 11,11-Diphenyl-8-benzo[c]fluorenyl, 11,11-Diphenyl-9-benzo[c]fluorenyl, 11,11-Diphenyl-10-benzo[c]fluorenyl, 9,9,10,10-tetramethyl-9,10-dihydro-1-phenanthyl, 9,9,10,10-tetramethyl-9,10-dihydro-2-phenanthyl, 9,9,10,10-tetramethyl-9,10-dihydro-3-phenanthyl, 9,9,10,10-tetramethyl-9,10-dihydro-4-phenanthyl, etc.

[0038] In this application, the term "heteroaryl" refers to an aryl group having a ring skeleton atom comprising at least one heteroatom selected from the group consisting of B, N, O, S, Si, P, Se, and Ge, preferably at least one heteroatom selected from N, O, and S, wherein the number of ring skeleton carbon atoms is preferably 3 to 30, 3 to 22, 3 to 20, 3 to 15, 3 to 12, etc. The number of heteroatoms in a heteroaryl group is preferably 1 to 4. The aforementioned heteroaryl group can be a monocyclic ring or a fused ring condensed with at least one benzene ring; and can be partially saturated. Furthermore, in this document, the aforementioned heteroaryl group can be a heteroaryl group formed by linking at least one heteroaryl group or aryl group to a heteroaryl group via one or more single bonds. Specific examples of heteroaryl groups can include monocyclic heteroaryl groups, including furanyl, thiopheneyl, pyrroleyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetraazinyl, triazolyl, tetraazolyl, furazanyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, etc., and fused-ring heteroaryl groups, including benzofuranyl, benzothiopheneyl, isobenzofuranyl, dibenzofuranyl, etc. Benzyl, dibenzothiophene, dibenzoselenophene, benzofuranoquinolinyl, benzofuranoquinazolinyl, benzofuranonaphthidyl, benzofuranopyrimidyl, naphthofuranopyrimidyl, benzothiophenequinolinyl, benzothiophenequinazolinyl, benzothiophene naphthophenidyl, benzothiophene pyrimidyl, naphthophene pyrimidyl, pyrimidylindolyl, benzopyrimidylindolyl, benzofuranopyrazinyl, naphthofurano Pyrazinyl, benzothiophene-pyrazinyl, naphthothiophene-pyrazinyl, pyrazinodolyl, benzopyrazinodolyl, benzimidazolyl, benzothiazolyl, benzoisothiazolyl, benzoisooxazolyl, benzooxazolyl, imidazopyridyl, isoindodolyl, indodolyl, benzoindodolyl, indazoleyl, benzothiadiazolyl, quinolinyl, isoquinolinyl, cenolinyl, quinazolinyl, quinoxalolinyl, carbazoleyl, azacarbazoleyl, benzocarbazoleyl Azolyl, dibenzocarbazoyl, phenoxazinyl, phenanthidyl, benzodioxanepentenyl, indololinyl, acridineyl, silafluorenyl, germanfluorenyl, benzotriazolyl, phenazinyl, imidazopyridyl, benzopyranoquinazolinyl, thiobenzopyranoquinazolinyl, dimethylbenzopyrimidinyl, indolocarbazoyl, indenecarbazoyl, etc. More specifically, heteroaryl groups can be 1-pyrrolithyl, 2-pyrrolithyl, 3-pyrrolithyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 6-pyrimidinyl, 1,2,3-triazin-4-yl, 1,2,4-triazin-3-yl, 1,3,5-Triazine-2-yl, 1-Imidazolyl, 2-Imidazolyl, 1-Pyrazolyl, 1-Indolithidyl, 2-Indolithidyl, 3-Indolithidyl, 5-Indolithidyl, 6-Indolithidyl, 7-Indolithidyl, 8-Indolithidyl, 2-Imidazolopyridyl, 3-Imidazolopyridyl, 5-Imidazolopyridyl, 6-Imidazolopyridyl 1-Indolyl, 2-Indolyl, 3-Indolyl, 4-Indolyl, 5-Indolyl, 6-Indolyl, 7-Indolyl, 1-Isoindolyl, 2-Isoindolyl, 3-Isoindolyl, 4-Isoindolyl, 5-Isoindolyl, 6-Isoindolyl, 7-Isoindolyl, 2-Furfuryl, 3-Furfuryl, 2- Benzofuranyl, 3-benzofuranyl, 4-benzofuranyl, 5-benzofuranyl, 6-benzofuranyl, 7-benzofuranyl, 1-isobenzofuranyl, 3-isobenzofuranyl, 4-isobenzofuranyl, 5-isobenzofuranyl, 6-isobenzofuranyl, 7-isobenzofuranyl, 2-quinolinyl, 3-quinolinyl, 4-quinolinyl, 5-quinolinyl 6-Quinolinyl, 7-Quinolinyl, 8-Quinolinyl, 1-Isoquinolinyl, 3-Isoquinolinyl, 4-Isoquinolinyl, 5-Isoquinolinyl, 6-Isoquinolinyl, 7-Isoquinolinyl, 8-Isoquinolinyl, 2-Quinoxolinyl, 5-Quinoxolinyl, 6-Quinoxolinyl, 1-Carbazoleyl, 2-Carbazoleyl, 3-Carbazoleyl, 4-Carbazoleyl, 9-Carbazoleyl, Azacarbazoleyl-1 -yl, azacarbazole-2-yl, azacarbazole-3-yl, azacarbazole-4-yl, azacarbazole-5-yl, azacarbazole-6-yl, azacarbazole-7-yl, azacarbazole-8-yl, azacarbazole-9-yl, 1-phenanthridyl, 2-phenanthridyl, 3-phenanthridyl, 4-phenanthridyl, 6-phenanthridyl, 7-phenanthridyl, 8-phenanthridyl, 9-phenanthridyl, 1 0-Phenyridyl, 1-Acridinel, 2-Acridinel, 3-Acridinel, 4-Acridinel, 9-Acridinel, 2-Oxazolyl, 4-Oxazolyl, 5-Oxazolyl, 2-Oxadiazolyl, 5-Oxadiazolyl, 3-Furazonyl, 2-Thienyl, 3-Thienyl, 2-Methylpyrrole-1-yl, 2-Methylpyrrole-3-yl, 2-Methylpyrrole-4-yl, 2-Methylpyrrole -5-yl, 3-methylpyrrolo-1-yl, 3-methylpyrrolo-2-yl, 3-methylpyrrolo-4-yl, 3-methylpyrrolo-5-yl, 2-tert-butylpyrrolo-4-yl, 3-(2-phenylpropyl)pyrrolo-1-yl, 2-methyl-1-indolyl, 4-methyl-1-indolyl, 2-methyl-3-indolyl, 4-methyl-3-indolyl, 2-tert-butyl-1-indolyl, 4-tert-butyl-1-indolyl, 2-tert-butyl-3-indolyl, 4-tert-butyl-3-indolyl, 1-dibenzofuranyl, 2-dibenzofuranyl, 3-dibenzofuranyl, 4-dibenzofuranyl, 1-dibenzothiophene, 2-dibenzothiophene, 3-dibenzothiophene, 4-dibenzothiophene, 1-naphtho-[1,2-[b]-benzofuranyl, 2-naphtho-[1,2-b]-benzofuranyl, 3-naphtho-[1,2-b]-benzofuranyl, 4-naphtho-[1,2-b]-benzofuranyl, 5-naphtho-[1,2-b]-benzofuranyl, 6-naphtho-[1,2-b]-benzofuranyl, 7-naphtho-[1,2-b]-benzofuranyl 8-Naphtho-[1,2-b]-benzofuranyl, 9-Naphtho-[1,2-b]-benzofuranyl, 10-Naphtho-[1,2-b]-benzofuranyl, 1-Naphtho-[2,3-b]-benzofuranyl, 2-Naphtho-[2,3-b]-benzofuranyl, 3-Naphtho-[2,3-b]-benzofuranyl, 4-Naphtho-[2, [3-b]-benzofuranyl, 5-naphtho-[2,3-b]-benzofuranyl, 6-naphtho-[2,3-b]-benzofuranyl, 7-naphtho-[2,3-b]-benzofuranyl, 8-naphtho-[2,3-b]-benzofuranyl, 9-naphtho-[2,3-b]-benzofuranyl, 10-naphtho-[2,3-b]-benzofuran 1-Naphtho-[2,1-b]-benzofuranyl, 2-Naphtho-[2,1-b]-benzofuranyl, 3-Naphtho-[2,1-b]-benzofuranyl, 4-Naphtho-[2,1-b]-benzofuranyl, 5-Naphtho-[2,1-b]-benzofuranyl, 6-Naphtho-[2,1-b]-benzofuranyl, 7-Naphtho-[2, 1-b]-benzofuranyl, 8-naphtho-[2,1-b]-benzofuranyl, 9-naphtho-[2,1-b]-benzofuranyl, 10-naphtho-[2,1-b]-benzofuranyl, 1-naphtho-[1,2-b]-benzothiophenyl, 2-naphtho-[1,2-b]-benzothiophenyl, 3-naphtho-[1,2-b]-benzothiophene 4-Naphtho-[1,2-b]-benzothiophene, 5-Naphtho-[1,2-b]-benzothiophene, 6-Naphtho-[1,2-b]-benzothiophene, 7-Naphtho-[1,2-b]-benzothiophene, 8-Naphtho-[1,2-b]-benzothiophene, 9-Naphtho-[1,2-b]-benzothiophene, 10-Naphtho-[1 [2,3-b]-benzothiophene, 1-naphtho-[2,3-b]-benzothiophene, 2-naphtho-[2,3-b]-benzothiophene, 3-naphtho-[2,3-b]-benzothiophene, 4-naphtho-[2,3-b]-benzothiophene, 5-naphtho-[2,3-b]-benzothiophene, 1-naphtho-[2,1-b]-benzothiophene 2-Naphtho-[2,1-b]-benzothiophene, 3-Naphtho-[2,1-b]-benzothiophene, 4-Naphtho-[2,1-b]-benzothiophene, 5-Naphtho-[2,1-b]-benzothiophene, 6-Naphtho-[2,1-b]-benzothiophene, 7-Naphtho-[2,1-b]-benzothiophene, 8-Naphtho-[2,1-b]-benzothiophene1-b]-benzothiophene, 9-naphtho-[2,1-b]-benzothiophene, 10-naphtho-[2,1-b]-benzothiophene, 2-benzofurano[3,2-d]pyrimidinyl, 6-benzofurano[3,2-d]pyrimidinyl, 7-benzofurano[3,2-d]pyrimidinyl, 8-benzofurano[3,2-d]pyrimidinyl, 9-benzofurano[3,2-d]pyrimidinyl, 2-benzothio[3,2-d]pyrimidinyl, 6-benzothio[3,2-d]pyrimidinyl, 7-benzothio[3,2-d]pyrimidinyl, 8-benzothio[3,2-d]pyrimidinyl, 9-benzothio[3,2-d]pyrimidinyl, 2-benzofurano[3,2-d]pyrazinyl 6-Benzofurano[3,2-d]pyrazinyl, 7-Benzofurano[3,2-d]pyrazinyl, 8-Benzofurano[3,2-d]pyrazinyl, 9-Benzofurano[3,2-d]pyrazinyl, 2-Benzothio[3,2-d]pyrazinyl, 6-Benzothio[3,2-d]pyrazinyl, 7-Benzothio[3,2-d]pyrazinyl Phthalinyl, 8-benzothio[3,2-d]pyrazinyl, 9-benzothio[3,2-d]pyrazinyl, 1-silylfluorenyl, 2-silylfluorenyl, 3-silylfluorenyl, 4-silylfluorenyl, 1-germaniumfluorenyl, 2-germaniumfluorenyl, 3-germaniumfluorenyl, 4-germaniumfluorenyl, 1-dibenzo[2,3-]selenophenyl, 2-dibenzo[2,3-]selenophenyl, 3-dibenzo[2,3-]selenophenyl, 4-dibenzo[2,3-]selenophenyl, etc.

[0039] Furthermore, the term "substituted" in the expression "substituted or unsubstituted" means that a hydrogen atom in a functional group is replaced by another atom or functional group (i.e., a substituent). Preferably, in this application, the substituted substituents include, but are not limited to, those independently selected from deuterium, aryl groups having 6 to 20 carbon atoms, and heteroaryl groups having 3 to 20 carbon atoms. Further options include deuterium, phenyl, naphthyl, phenanthryl, dibenzothiophene, dibenzofuranyl, benzonaphthothiophene, benzonaphthofuranyl, etc.

[0040] The bistriarylamine compounds of the present invention will be described below.

[0041] This invention provides a bis(triarylamine) compound having the structure shown in formula (a):

[0042]

[0043] Ar1 to Ar4 may be the same as or different from each other, and each is independently selected from aryl groups with 6 to 22 substituted or unsubstituted carbon atoms and heteroaryl groups with 3 to 30 substituted or unsubstituted carbon atoms, and satisfies the condition that at least one of Ar1 to Ar4 is selected from the group described in formula (b1), and at least one is selected from the group described in formula (b2).

[0044]

[0045] In some embodiments of the present invention, Ar1 to Ar4 are each independently selected from aryl groups having 6 to 22 carbon atoms, or heteroaryl groups having 3 to 30 carbon atoms, whether substituted or unsubstituted. The substituents in "substituted or unsubstituted" include, but are not limited to, those independently selected from deuterium, aryl groups having 6 to 20 carbon atoms, or heteroaryl groups having 3 to 20 carbon atoms. Further, the substituents in "substituted or unsubstituted" may be deuterium, phenyl, naphthyl, phenanthryl, dibenzothiophene, dibenzofuranyl, benzonaphthothiophene, benzonaphthofuranyl, etc.

[0046] In some embodiments of the present invention, Ar1 to Ar4 are each independently selected from aryl groups having 6 to 20 carbon atoms, or heteroaryl groups having 3 to 20 carbon atoms, whether substituted or unsubstituted. Herein, "substituted" means that any hydrogen atom in any of the aforementioned groups is replaced by a substituent. Specifically, the substituents in "substituted or unsubstituted" include, but are not limited to, those independently selected from deuterium, aryl groups having 6 to 20 carbon atoms, and heteroaryl groups having 3 to 20 carbon atoms. Further, the substituents in "substituted or unsubstituted" may be deuterium, phenyl, naphthyl, phenanthrene, dibenzothiophene, dibenzofuranyl, benzonaphthothiophene, benzonaphthofuranyl, etc.

[0047] In some embodiments of the present invention, Ar1 to Ar4 are each independently selected from aryl groups having 6 to 18 carbon atoms, or heteroaryl groups having 3 to 18 carbon atoms, whether substituted or unsubstituted. Here, "substituted" means that any hydrogen atom in any of the aforementioned groups is replaced by a substituent. Specifically, the substituents in "substituted or unsubstituted" include, but are not limited to, those independently selected from deuterium, aryl groups having 6 to 20 carbon atoms, or heteroaryl groups having 3 to 20 carbon atoms. Further, the substituents in "substituted or unsubstituted" may be deuterium, phenyl, naphthyl, phenanthryl, dibenzothiophene, dibenzofuranyl, benzonaphthothiophene, benzonaphthofuranyl, etc.

[0048] In some embodiments of the present invention, Ar1 to Ar4 are each independently selected from aryl groups having 6 to 16 carbon atoms, or heteroaryl groups having 3 to 16 carbon atoms, whether substituted or unsubstituted. Here, "substituted" means that any hydrogen atom in any of the aforementioned groups is replaced by a substituent. Specifically, the substituents in "substituted or unsubstituted" include, but are not limited to, those independently selected from deuterium, aryl groups having 6 to 20 carbon atoms, or heteroaryl groups having 3 to 20 carbon atoms. Further, the substituents in "substituted or unsubstituted" may be deuterium, phenyl, naphthyl, phenanthryl, dibenzothiophene, dibenzofuranyl, benzonaphthothiophene, benzonaphthofuranyl, etc.

[0049] In some embodiments of the present invention, Ar1 to Ar4 are each independently selected from aryl groups having 6 to 12 carbon atoms, or heteroaryl groups having 3 to 12 carbon atoms, whether substituted or unsubstituted. Herein, "substituted" means that any hydrogen atom in any of the aforementioned groups is replaced by a substituent. Specifically, the substituents in "substituted or unsubstituted" include, but are not limited to, those independently selected from deuterium, aryl groups having 6 to 20 carbon atoms, or heteroaryl groups having 3 to 20 carbon atoms. Further, the substituents in "substituted or unsubstituted" may be deuterium, phenyl, naphthyl, phenanthryl, dibenzothiophene, dibenzofuranyl, benzonaphthothiophene, benzonaphthofuranyl, etc.

[0050] In some embodiments of the present invention, Ar1 to Ar4 are each independently selected from the following substituted or unsubstituted groups: phenyl, diphenyl, naphthyl, phenanthrene, dibenzothiophene, dibenzofuranyl, benzonaphthothiophene, and benzonaphthofuranyl. Wherein, "substituted" means that any hydrogen atom in any of the above groups is replaced by a substituent. Specifically, the substituents in "substituted or unsubstituted" include, but are not limited to, those independently selected from deuterium, aryl groups having 6 to 20 carbon atoms, and heteroaryl groups having 3 to 20 carbon atoms. Further, the substituents in "substituted or unsubstituted" may be deuterium, phenyl, naphthyl, phenanthrene, dibenzothiophene, dibenzofuranyl, benzonaphthothiophene, benzonaphthofuranyl, etc.

[0051] In some embodiments of the present invention, m represents the number of R1s, n represents the number of R2s, and r represents the number of R5s. m, n, and r are each independently selected from integers between 0 and 4. Optionally, m is 0, 1, 2, 3, or 4; n is 0, 1, 2, 3, or 4; and r is 0, 1, 2, 3, or 4.

[0052] In some embodiments of the present invention, p represents the number of R3s and q represents the number of R4s. p and q are each independently selected from integers between 0 and 7. Optionally, p is 0, 1, 2, 3, 4, 5, 6, 7, and q is 0, 1, 2, 3, 4, 5, 6, 7.

[0053] In some embodiments of the present invention, R1 to R5 may be the same or different from each other each time they appear, and each is independently selected from deuterium, phenyl, and naphthyl.

[0054] In some embodiments of the present invention, the bistriarylamine compound is selected from any one of the following structures:

[0055]

[0056] In the above chemical formulas, Ar1~Ar4, m,n,r,p,q,R1~R5 represent the same meanings as described above.

[0057] In some optional embodiments of the present invention, the bistriarylamine compound is selected from any one of the following structures:

[0058]

[0059]

[0060] In the above chemical formulas, the symbols in each structural formula have the same meaning as described above.

[0061] In some preferred embodiments of the present invention, the compound represented by formula (a) is selected from any of the following chemical structures:

[0062]

[0063]

[0064] The following will describe the functional layer that applies the above-mentioned bis(triarylamine) compounds, as well as the organic electroluminescent device, display or lighting device that includes the functional layer.

[0065] This application also provides an organic electroluminescent device, comprising a first electrode, a second electrode, and the aforementioned organic layer. As an example, the first electrode is an anode, and the second electrode is a cathode, which may be one or more layers. The organic layer is located between the first electrode and the second electrode. The organic layer may be a single-layer structure or a multilayer tandem structure with two or more organic layers laminated together. The organic layer includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, and an electron transport layer. In some preferred embodiments, the bis(triarylamine) compounds of this application are used as electron blocking layer materials, hole transport layer materials, or the host material of the light-emitting layer.

[0066] In some specific embodiments, the structure of the organic electroluminescent device may be selected from one of the following:

[0067] (1) An organic electroluminescent device includes an anode, a hole injection layer, a first hole transport layer, a light-emitting layer, a first electron transport layer, and a cathode stacked in sequence, that is, anode / hole injection layer / first hole transport layer / light-emitting layer / first electron transport layer / cathode. The device structure will be expressed in this simplified way below.

[0068] (2) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / cathode.

[0069] (3) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / second electron transport layer / cathode.

[0070] (4) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / second electron transport layer / electron injection layer / cathode.

[0071] (5) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / second electron transport layer / multilayer cathode.

[0072] (6) Anode / hole injection layer / first hole transport layer / first light-emitting layer / carrier generation layer / first hole transport layer / second light-emitting layer / first electron transport layer / cathode.

[0073] (7) Anode / hole injection layer / first hole transport layer / first light-emitting layer / carrier generation layer / first hole transport layer / second light-emitting layer / first electron transport layer / second electron transport layer / cathode.

[0074] (8) Anode / hole injection layer / second hole transport layer / first hole transport layer / first light-emitting layer / carrier generation layer / first hole transport layer / second light-emitting layer / first electron transport layer / cathode.

[0075] (9) Anode / hole injection layer / second hole transport layer / first hole transport layer / first light-emitting layer / carrier generation layer / first hole transport layer / second light-emitting layer / first electron transport layer / second electron transport layer / cathode.

[0076] (10) Anode / hole injection layer / hole transport layer / electron blocking layer / light emission layer / electron transport layer / electron injection layer / cathode.

[0077] (11) Anode / hole injection layer / first hole transport layer / second hole transport layer / light-emitting layer / hole blocking layer / electron transport layer / cathode.

[0078] (12) Anode / hole injection layer / hole transport layer / electron blocking layer / light emitting layer / electron transport layer / cathode.

[0079] (13) Anode / hole injection layer / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / cathode.

[0080] The organic electroluminescent device can emit light from either the anode side or the cathode side. In some specific embodiments, it emits light from the cathode side, which requires adding a capping layer on the cathode side, as shown in the following structure:

[0081] 1) Anode / hole injection layer / first hole transport layer / light emission layer / first electron transport layer / cathode / capping layer.

[0082] 2) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / cathode / capping layer.

[0083] 3) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / second electron transport layer / cathode / capping layer.

[0084] 4) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / second electron transport layer / electron injection layer / cathode / capping layer.

[0085] 5) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / second electron transport layer / multilayer cathode / capping layer.

[0086] 6) Anode / hole injection layer / first hole transport layer / first light-emitting layer / carrier generation layer / first hole transport layer / second light-emitting layer / first electron transport layer / cathode / capping layer.

[0087] 7) Anode / Hole Injection Layer / First Hole Transport Layer / First Light Emitting Layer / Carrier Generation Layer / First Hole Transport Layer / Second Light Emitting Layer / First Electron Transport Layer / Second Electron Transport Layer / Cathode / Covering Layer.

[0088] 8) Anode / Hole Injection Layer / Second Hole Transport Layer / First Hole Transport Layer / First Light Emitting Layer / Carrier Generation Layer / First Hole Transport Layer / Second Light Emitting Layer / First Electron Transport Layer / Cathode / Covering Layer.

[0089] 9) Anode / Hole Injection Layer / Second Hole Transport Layer / First Hole Transport Layer / First Light Emitting Layer / Carrier Generation Layer / First Hole Transport Layer / Second Light Emitting Layer / First Electron Transport Layer / Second Electron Transport Layer / Cathode / Covering Layer.

[0090] 10) Anode / hole injection layer / hole transport layer / electron blocking layer / light emission layer / electron transport layer / electron injection layer / cathode / capping layer.

[0091] 11) Anode / Hole injection layer / First hole transport layer / Second hole transport layer / Light emission layer / Hole blocking layer / Electron transport layer / Cathode / Covering layer.

[0092] 12) Anode / hole injection layer / hole transport layer / electron blocking layer / light emission layer / electron transport layer / cathode / capping layer.

[0093] 13) Anode / hole injection layer / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / cathode / capping layer (device structure of the blue light embodiment of this application).

[0094] The following describes some specific functional layers in the organic electroluminescent device.

[0095] Substrate:

[0096] The substrate is generally located below the anode. The substrate can be made of plastic or glass, and can be rigid or flexible. The substrate has a driving unit that can drive the corresponding pixel to emit light.

[0097] anode:

[0098] Organic EL (Organic Electro-Luminescence) devices typically require the anode to have good conductivity, a smooth surface, and be resistant to cracking. They also have certain requirements for work function, mainly to match the hole injection layer and achieve the hole injection effect.

[0099] When using a top-emitting method (cathode-side light emission), the anode is a metal compound with a work function of 4.2 eV or higher, such as indium tin oxide, tin oxide, indium zinc oxide, gold, silver, platinum, copper, carbon nanotubes, carbon nanowires, graphene, etc. The thickness is 10 nm to 200 nm, preferably 10 nm to 50 nm. A reflective electrode is placed below the anode (near the substrate end). The reflective electrode is generally made of metal or metal alloy, such as silver, copper, aluminum, gold, or alloys of these metals with other metals. The reflective electrode has high reflectivity, requiring a reflectivity of over 90%, and its thickness is typically between 100 nm and 500 nm, preferably in the range of 80 nm to 150 nm.

[0100] When bottom-emitting (light emission from the cathode side) is used, the anode is a metal compound with a work function of 4.2 eV or higher, such as indium tin oxide alloy, tin oxide, indium zinc oxide, gold, silver, platinum, copper, carbon nanotubes, carbon nanowires, graphene, etc. The thickness is 10 nm to 1 μm, preferably 50 nm to 200 nm.

[0101] The anode can be made by forming a thin film from the electrode material using methods such as vapor deposition, sputtering, or coating.

[0102] Hole injection layer:

[0103] The thickness of the hole injection layer is typically 3 nm to 20 nm. The hole injection layer uses a mixture of P-type and hole transport materials. The purpose of using P-type materials is to accept holes from the anode and transfer them to the hole transport material. The weight percentage of P-type materials in the hole injection layer is typically 0.5% to 10%. When the weight percentage is 0.5% to 3%, the absolute value of the difference between the lowest unoccupied molecular orbital (LUMO) energy level of the P-type material and the highest occupied molecular orbital (HOMO) energy level of the HTL material must not exceed 0.3 eV. When the weight percentage is 3% to 5%, the absolute value of the difference between the lowest unoccupied molecular orbital (LUMO) energy level of the P-type material and the highest occupied molecular orbital (HOMO) energy level of the HTL material must not exceed 0.5 eV. When the weight percentage is 5% to 10%, the absolute value of the difference between the lowest unoccupied molecular orbital (LUMO) energy level of the P-type material and the highest occupied molecular orbital (HOMO) energy level of the HTL material must not exceed 1 eV.

[0104] P-type materials can be metal oxides, such as molybdenum oxide, vanadium oxide, and tungsten oxide; they can also be organic compounds, such as 4,4',4”-((1E,1'E,1”E)-cyclopropane-1,2,3-trimethylenetris(cyanoformyl))tris(2,3,5,6-tetrafluorobenzyl) (PD1, CAS No.: 1224447-88-4), tetracyanoquinone dimethyl (TCNQ), 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinone dimethyl (F4-TCNQ), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN), and are not limited to these. The hole transport material paired with the P-type material can be selected from the material of the second hole transport layer, and can be the same as or different from the material of the second hole transport layer.

[0105] Second hole transport layer:

[0106] The thickness of the second hole transport layer is typically 40 nm to 150 nm, and it often uses aryl amine compounds, such as monoaryl amines or polyaryl amines. Hole transport materials are required to have high hole mobility, reduce driving voltage, and have a glass transition temperature exceeding 100°C to avoid crystallization at high temperatures.

[0107] First hole transport layer:

[0108] The thickness of the first hole transport layer is typically 3nm to 220nm. When there is no second hole transport layer, the thickness of the first hole transport layer is typically 40nm to 150nm; when there is a second hole transport layer, the thickness of the first hole transport layer is typically 3nm to 120nm. Generally, red, green, blue, and yellow light require thickness adjustments based on the "microcavity effect," and the thickness selection varies. Taking a top-emitting device as an example, the formula for the microcavity is as follows:

[0109]

[0110] Where n i ,d i The refractive index coefficient and thickness of the i-th layer are respectively identified, m is an integer and is the modulus of the microcavity, which is more commonly 1 or 2; θ1 and θ2 represent the phase shifts generated by light at the anode and cathode interfaces, respectively.

[0111] Red, green, blue, and other colored light have different wavelengths, so each color has its optimal thickness. Taking a modulus of 2 as an example, for red light, without a second hole transport layer, the thickness of the first hole transport layer is generally 160nm–220nm; with a second hole transport layer, the thickness of the first hole transport layer is generally 8nm–120nm. For green light, without a second hole transport layer, the thickness of the first hole transport layer is generally 100nm–180nm; with a second hole transport layer, the thickness of the first hole transport layer is generally 30nm–70nm. For blue light, without a second hole transport layer, the thickness of the first hole transport layer is generally 80nm–130nm; with a second hole transport layer, the thickness of the first hole transport layer is generally 3nm–30nm. Different optimal "microcavity adjustment thicknesses" will be selected for other colors.

[0112] Electron blocking layer:

[0113] The electron blocking layer can simultaneously possess both hole transport and electron blocking functions. Furthermore, the higher triplet excitation energy level of the electron blocking layer can confine excitons generated in the emissive layer within it, thereby improving the device's luminous efficiency.

[0114] Emissive layer:

[0115] The material of the light-emitting layer generally includes a host material and a guest dopant material, wherein the content of the host material is greater than that of the guest dopant material. Optionally, the mass percentage of the guest dopant material in the light-emitting layer is 1% to 20%.

[0116] Guest dopants used as luminescent materials can include phosphorescent or fluorescent materials or thermally activated delayed fluorescence materials. Red, green, and blue light can be selected from these three types of guest dopants. For example, the guest dopant material for the luminescent layer corresponding to a red luminescent unit and the luminescent layer corresponding to a green luminescent unit is a phosphorescent material, while the guest dopant material for the luminescent layer corresponding to a blue luminescent unit is a fluorescent material.

[0117] For example, the guest doping material of the light-emitting layer corresponding to the light-emitting unit with a red emission color and the light-emitting layer corresponding to the light-emitting unit with a green emission color is a phosphorescent material, and the guest doping material of the light-emitting layer corresponding to the light-emitting unit with a blue emission color is a phosphorescent material.

[0118] For example, the guest doping material of the light-emitting layer corresponding to the light-emitting unit with a red emission color and the light-emitting layer corresponding to the light-emitting unit with a green emission color is a thermally activated delayed fluorescence material, and the guest doping material of the light-emitting layer corresponding to the light-emitting unit with a blue emission color is a fluorescent material.

[0119] For example, the guest doping material of the light-emitting layer corresponding to the light-emitting unit with a red emission color and the light-emitting layer corresponding to the light-emitting unit with a green emission color is a thermally activated delayed fluorescence material, and the guest doping material of the light-emitting layer corresponding to the light-emitting unit with a blue emission color is a phosphorescent material.

[0120] To reduce the power consumption of organic light-emitting display panels in organic electroluminescent devices, guest doping materials with superior luminescent properties can be selected. Taking a top-emitting device as an example, optionally, the light-emitting unit with a red emission color has a luminous intensity of 1000 cd / m². 2 A green light-emitting unit with a current efficiency greater than 30 cd / A and a luminous intensity of 6000 cd / m² is used. 2 A light-emitting unit with a current efficiency greater than 100 cd / A and a fluorescent blue emission color has a luminous intensity of 1000 cd / m². 2 With a current efficiency greater than 5 cd / A as the standard, and by selecting suitable guest doping materials, a phosphorescent blue emitting unit is achieved with a luminous intensity of 1000 cd / m². 2 The standard is a current efficiency greater than 10 cd / A. Higher current efficiency can reduce power consumption.

[0121] As the main light-emitting material, one or two main light-emitting materials can be selected.

[0122] Cavity blocking layer:

[0123] To enhance the balance between hole and electron concentrations, a hole blocking layer is inserted to balance carrier concentration and prevent exciton quenching. Typically, the hole blocking layer is located between the emitting layer and the electron transport layer, and the hole blocking layer material must meet conditions such as high stability, good film-forming properties, and a sufficiently high highest molecular occupied orbital.

[0124] First electron transport layer:

[0125] The thickness of the first electron transport layer can typically be 3nm–40nm, 3nm–10nm, 10nm–20nm, 20nm–30nm, 30nm–40nm, or 20nm–40nm. When there is no second electron transport layer, the thickness of the first electron transport layer is typically 20nm–50nm; when there is a second electron transport layer, the thickness of the first electron transport layer is typically 40nm–20nm. The first electron transport layer is in direct contact with the emitting layer, and therefore, similar to the first hole transport layer, it also undergoes electronic changes during electron transport, leading to increased molecular vibration and deformation. Furthermore, the interaction between the excitons of the emitting layer and the polarons of the electron transport material can easily generate reactive free radicals, which can damage the electron transport material. The electron transport material can be a single compound or a mixture of other metals or metal compounds. It can include mixtures of organic electron transport materials and metal compounds, or mixtures of organic electron transport materials and metals.

[0126] When organic electron transport materials are mixed with metal compound materials, such as alkali metal compounds, alkaline earth metal compounds, and rare earth metal compounds, more specifically, they can be mixed with lithium metal compounds, calcium metal compounds, Mg metal compounds, samarium metal compounds, ytterbium metal compounds, etc., and even more specifically, they can be mixed with lithium 8-hydroxyquinoline, lithium fluoride, magnesium fluoride, ytterbium fluoride, calcium fluoride, etc. When used in combination with metal compounds, the mass percentage of the organic electron transport material can be 20%–80%, 20%–40%, 40%–60%, or 60%–80%, etc.

[0127] When organic electron transport materials are used in combination with metals, such as alkali metals, alkaline earth metals, and rare earth metals, or more specifically, with lithium metal, magnesium metal, calcium metal, ytterbium metal, and samarium metal, the mass ratio of the organic electron transport material can be 80%–99%, 80%–89%, 89%–99%, 80%–85%, 85%–90%, 90%–95%, or 95%–99%, etc.

[0128] Second electron transport layer:

[0129] The thickness of the second electron transport layer is generally 10 nm to 40 nm. The material of the second electron transport layer may include a mixture of organic electron transport materials and metal compounds, or a mixture of organic electron transport materials and metals.

[0130] When organic electron transport materials are mixed with metal compound materials, such as alkali metal compounds, alkaline earth metal compounds, and rare earth metal compounds, more specifically, they can be mixed with lithium metal compounds, calcium metal compounds, Mg metal compounds, samarium metal compounds, ytterbium metal compounds, etc., and even more specifically, they can be mixed with lithium 8-hydroxyquinoline, lithium fluoride, magnesium fluoride, ytterbium fluoride, calcium fluoride, etc. When used in combination with metal compounds, the mass percentage of the organic electron transport material can be 20%–80%, 20%–40%, 40%–60%, or 60%–80%, etc.

[0131] When organic electron transport materials are used in combination with metals, such as alkali metals, alkaline earth metals, and rare earth metals, or more specifically, with lithium metal, magnesium metal, calcium metal, ytterbium metal, and samarium metal, the mass ratio of the organic electron transport material can be 80%–99%, 80%–89%, 89%–99%, 80%–85%, 85%–90%, 90%–95%, or 95%–99%, etc.

[0132] Charge generation layer:

[0133] When a single-layer light-emitting device is used, holes and electrons are injected from the anode and cathode respectively, eliminating the need for a charge generation layer. When using double or multiple light-emitting layers, a charge generation layer is required between the light-emitting layers to achieve charge generation, injection, and transport. This charge generation layer is located between the two light-emitting layers and is typically composed of two P / N type materials. The P-type material is selected from the hole injection materials mentioned earlier, while the N-type material is a mixture of organic electron transport materials and metals. The organic electron transport layer material is selected from the second electron transport layer mentioned earlier, and the metal is selected from alkali metals, alkaline earth metals, and rare earth metals. More specifically, examples include lithium, magnesium, calcium, ytterbium, and samarium. When organic electron transport materials are mixed with metals, the mass percentage of the organic electron transport material can be 80%–99%, 80%–89%, 89%–99%, 80%–85%, 85%–90%, 90%–95%, or 95%–99%, etc.

[0134] cathode:

[0135] The cathode requires materials with good electrical conductivity and a smooth surface. To improve electron injection capability, materials with a low work function are typically chosen. Cathode materials can be single-layer, double-layer, or multi-layer cathodes, generally made of metals or metal alloys. For single-layer cathodes, silver, copper, aluminum, gold, or alloys of these metals with other metals, such as rare earth metals, alkali metals, and alkaline earth metals, can be used. Examples include magnesium-indium alloys, magnesium-aluminum alloys, aluminum-potassium alloys, aluminum-scandium-potassium alloys, magnesium-silver alloys, silver-ytterbium alloys, and silver-samarium alloys. If a double-layer metal cathode is used, the cathode layer closer to the light-emitting layer can be made of alkali metals, alkaline earth metals, or rare earth metals, such as lithium, calcium, magnesium, and ytterbium, to increase electron injection capability. The cathode layer farther from the light-emitting side is mainly used to improve conductivity, and generally uses silver, copper, aluminum, gold, or alloys of these metals with other metals, such as alloys with rare earth metals, alkali metals, or alkaline earth metals. Examples include magnesium-indium alloys, magnesium-aluminum alloys, aluminum-potassium alloys, aluminum-scandium-potassium alloys, magnesium-silver alloys, silver-ytterbium alloys, and silver-samarium alloys. The cathode can also be formed into a thin film using methods such as vapor deposition or sputtering.

[0136] When light comes out from the anode side, the cathode must be opaque, and a cathode with a thickness greater than 100 nm can be deposited. When light comes out from the cathode side, the cathode must be transparent, with a transmittance greater than 40% and a thickness of 10 nm to 20 nm.

[0137] Overlay:

[0138] The refractive index n and absorption coefficient of a single-layer capping layer must meet the following conditions:

[0139] The refractive index n(450~650nm) is >1.8 between wavelengths of 450~650nm, and the extinction coefficient between wavelengths of 450~650nm is less than 0.1; the extinction coefficient at 380nm is greater than 0.2; the difference between the refractive index at 450nm and the refractive index at 530nm is n(450nm)-n(530nm)<0.5, more preferably n(450nm)-n(530nm)<0.3; the difference between the refractive index at 510nm and the refractive index at 620nm is n(510nm)-n(620nm)<0.4, more preferably the difference between the refractive index at 510nm and the refractive index at 620nm is n(510nm)-n(620nm)<0.2.

[0140] Materials that can meet the requirements of the covering layer for refractive index n can further achieve high luminous efficiency of the device, while the luminous efficiency and viewing angle of red, green and blue light are more balanced.

[0141] In some specific embodiments, the thickness of the cover layer is 50nm to 90nm, for example, 50nm, 55nm, 57nm, 59nm, 62nm, 64nm, 67nm, 68nm, 70nm, 75nm, 77nm, 79nm, 80nm, 82nm, 85nm, 88nm, 90nm, etc.

[0142] The cover layer is formed after the semi-transparent cathode of the OLED display panel is away from the substrate, and the stack formed by the cover layer and the semi-transparent cathode can achieve a light transmittance of ≥65% for light between 450nm and 650nm, such as 68%, 69%, 73%, 77%, 79%, 83%, 88%, 93%, etc.

[0143] When using two capping layers, the refractive index n and absorption coefficient need to satisfy the following conditions:

[0144] The refractive index n450-650nm<1.8 in the 450-650nm wavelength range of the capping layer (first capping layer) near the cathode side, and the extinction coefficient in the 450-650nm wavelength range is less than 0.1; the maximum coefficient in any wavelength range of 250nm-350nm is greater than 0.3, and the optimal value is greater than 0.6.

[0145] The capping layer (second capping layer) away from the cathode has a refractive index n450-650nm>1.8 between wavelengths of 450-650nm, and an extinction coefficient between wavelengths of 450-650nm below 0.1; the extinction coefficient at 380nm is greater than 0.1, and more preferably greater than 0.2.

[0146] The difference between the refractive index of 450nm and the refractive index of 530nm, n(450nm)-n(530nm)<0.5, is more preferably n(450nm)-n(530nm)<0.3.

[0147] The difference between the refractive index of 510nm and 620nm, n(510nm)-n(620nm)<0.4, is even better than the difference between the refractive index of 450nm and 530nm, n(450nm)-n(530nm)<0.2.

[0148] The total thickness of the double-layer capping layer is 50nm to 90nm, for example: 50nm, 55nm, 57nm, 59nm, 62nm, 64nm, 67nm, 68nm, 70nm, 75nm, 77nm, 79nm, 80nm, 82nm, 85nm, 88nm, 90nm, etc.

[0149] The thickness of the capping layer (first capping layer) near the cathode side is 5nm to 40nm, for example: 5nm, 7nm, 10nm, 12nm, 15nm, 18nm, 20nm, 22nm, 25nm, 27nm, 30nm, 32nm, 34nm, 36nm, 38nm, 40nm, etc.

[0150] The thickness of the capping layer (second capping layer) away from the cathode side is 35nm to 85nm, for example: 35nm, 40nm, 43nm, 45nm, 48nm, 50nm, 55nm, 57nm, 59nm, 62nm, 64nm, 67nm, 68nm, 70nm, 75nm, 77nm, 79nm, 80nm, 82nm, 85nm, etc.

[0151] This application also provides a display device, including the aforementioned organic electroluminescent device.

[0152] Synthesis Example:

[0153] The specific preparation method of the above-mentioned new compounds of the present invention will be described in detail below using multiple synthetic examples. However, the preparation method of the present invention is not limited to these multiple synthetic examples. Those skilled in the art can make any modifications, equivalent substitutions, improvements, etc. on the basis of these examples without departing from the principles of the present invention, and extend the method to the scope of the technical solution claimed in the claims of the present invention.

[0154] Synthesis and Testing Methods

[0155] Raw materials and reagents

[0156] The initial raw materials and solvents of this invention were purchased from Shanghai Titan Technology Co., Ltd., and some commonly used OLED intermediates were purchased from domestic OLED intermediate manufacturers; various palladium catalysts and ligands were purchased from Shaanxi Ruike New Materials Co., Ltd.

[0157] [Cross-coupling synthesis]

[0158] The synthesis of the bis(triarylamine) compounds shown in formula (a) above can be carried out using known methods. For example, cross-coupling reactions using transition metals such as nickel and palladium can be used. Other synthetic methods use CC-CN coupling reactions using transition metals such as magnesium or zinc. The Suzuki-Buchwald reaction is preferred due to its mild reaction conditions and superior selectivity for various functional groups. The cycloalkanes and heterocyclic alkane derivatives of the present invention are illustrated by the following examples, but are not limited to the cycloalkanes and heterocyclic alkane derivatives and synthetic methods illustrated in these examples.

[0159] In an inert atmosphere, reaction A and the reactants are heated in an organic solvent in the presence of a cross-coupled catalyst (catalytic amount), with stirring under reflux during the reaction. After the required reaction time, the reaction system is cooled, water is added, and the precipitated solid is washed and then vacuum dried to obtain a crude product. The crude product is then purified (including but not limited to silica gel column chromatography) to obtain the final product.

[0160] [Testing Method]

[0161] 1 H NMR data were determined using a 400MHz nuclear magnetic resonance spectrometer (manufactured by Bruker GmbH, Germany); HPLC data were determined using a Waters Corporation UPLC ultra-high performance liquid chromatograph. Mass spectrometry was performed using a Waters Corporation single quadrupole mass spectrometer.

[0162] Synthesis of Compound 1:

[0163]

[0164] 1. Synthesis of intermediate compound 1-ii

[0165] Under a nitrogen atmosphere, 4'-bromo-2-chloro-1,1'-biphenyl (5.3 g, 20.0 mmol, 1 eq), compound 1-i (6.9 g, 20.0 mmol, 1 eq), and degassed anhydrous toluene (60 mL) were added sequentially to a dry three-necked flask. After thorough mixing, sodium tert-butoxide (2.9 g, 30.0 mmol, 1.5 eq), bis(benzylacetone)palladium (113 mg, 0.2 mmol, 1% eq), and tri-tert-butylphosphine (1.0 mL, 10% n-hexane solution, 0.4 mmol, 2% eq) were added. The mixture was stirred to thoroughly mix the reaction system, and then heated to reflux under a nitrogen atmosphere. After 8 hours of reaction, thin-layer chromatography analysis showed that there was essentially no reactant remaining, and heating was stopped. After the reaction system cooled to room temperature, a mixed solution of 5 mL concentrated hydrochloric acid (37% aqueous solution) and 100 mL deionized water was added. The mixture was allowed to stand and separate into layers. The layers were separated using a separatory funnel, and the organic phase was retained. The aqueous phase was extracted with toluene (3 × 20 mL) and combined with the retained organic phase. The solvent was removed by vacuum distillation. The crude product was then separated by silica gel column chromatography (the mobile phase was a mixture of n-hexane and toluene) to obtain compound 1-ii (8.6 g, yield 80.8%).

[0166] 2. Synthesis of Compound 1

[0167] The target compound 1 was synthesized following the method used to prepare intermediate compound 1-ii, except that the starting materials 4'-bromo-2-chloro-1,1'-biphenyl and compound 1-i were replaced by compounds 1-ii and 1-iii, respectively, in equivalent amounts. The crude product was sequentially separated by rapid silica gel column chromatography (using a hexane / dichloromethane mixed solvent as the mobile phase) and recrystallized from the crude product by an ethanol / toluene mixed solvent to obtain target compound 1 (8.3 g, yield 78.0%). The overall yield of the latter two steps was 63.0%. Mass spectrometry (m / z) = 665.29 [M+H] + .

[0168] Following the preparation method of compound 1, the compounds listed in Table 1 were synthesized. For each compound x, the starting materials or intermediates 1-i and 1-iii involved in the above preparation method are represented by xi and x-iii, respectively. The main starting materials used, the intermediates synthesized, the yields, and the mass spectrometry characterization data are shown in Table 1.

[0169] Table 1

[0170]

[0171]

[0172]

[0173] The NMR data of the representative compounds involved in the synthesis examples are shown in Table 2.

[0174] Table 2

[0175]

[0176]

[0177] Device Examples:

[0178] All compounds used in the device have been purified by sublimation, and their purity is greater than 99.98%.

[0179] The compounds involved in this invention can be used as electron blocking layer materials for various color OLED devices. The following section uses a blue light device as an example to provide specific device fabrication methods and test results.

[0180] Blue light device example 1:

[0181] According to such Figure 1The structure shown is used to fabricate a blue top-emitting organic electroluminescent device. The fabrication process is as follows: A transparent ITO film (150 nm thick) is formed on a glass substrate 101 by magnetron sputtering to obtain a first electrode 102 as the anode. A mixture of compound M1 and compound M2 is deposited on the anode surface as a hole injection layer 103, with a mixing ratio of 3:97 (mass ratio) and a thickness of 10 nm. Subsequently, compound M2 (100 nm thick) and compound 1 of the present invention (20 nm thick) are sequentially deposited on the surface of the hole injection layer to obtain a hole transport layer 104 and an electron blocking layer 105, respectively. Next, compound M3 and compound M4 are co-deposited on the surface of the electron blocking layer 105 at a mass ratio of 95:5 to form an organic light-emitting layer 106 (30 nm thick). Subsequently, compound M5 is sequentially deposited on the surface of the organic light-emitting layer to form a hole-blocking layer 107 (10 nm thick), and a mixture of compound M6 and LiQ in a 4:6 mass ratio is deposited to form an electron transport layer 108 (30 nm thick). Then, magnesium (Mg) and silver (Ag) are mixed and deposited on the surface of the electron transport layer 108 at a 1:9 evaporation rate to form a second electrode 109 with a thickness of 10 nm, serving as the cathode. Finally, compound M7 with a thickness of 70 nm is deposited as a capping layer 110, completing the fabrication of the organic light-emitting device.

[0182] During the fabrication of the aforementioned device, the vacuum level was maintained at 2 × 10⁻⁶ throughout the entire process. -7 Torr up to 5×10 -6 Between Torr; the evaporation rate of organic matter is between to Between these points, the evaporation rate of aluminum is This completes the manufacturing of organic light-emitting devices.

[0183] The chemical structures of compounds M1–M7 and LiQ are shown in Table 3.

[0184] Table 3

[0185]

[0186] Blue light device examples 2-16

[0187] Blue light devices Examples 2 to 16 were fabricated using the same method as in Example 1, except that, when forming the electron blocking layer, compound 1 was replaced with the compound listed in Table 4.

[0188] Comparative Examples 1-3

[0189] Except that when forming the light-emitting layer, compounds C1 to C3 (chemical structures shown below) were used to replace compound 1, the organic electroluminescent device was fabricated using the same method as in Example 1 of the blue light device.

[0190]

[0191] The operating voltage and efficiency of the organic electroluminescent device prepared above were calculated using a computer-controlled Keithley 2400 testing system (test current 20 mA / cm²). 2 Device lifetime under dark conditions was obtained using a Fostar lifetime measurement system equipped with a power supply and photodiode as detection units (test conditions: ambient temperature 25°C, constant current 20mA / cm). 2 LT95 refers to the time required for the brightness to decrease from its initial brightness to 95%. The test results are shown in Table 4.

[0192] Table 4

[0193]

[0194] The bis(triarylamine) compounds provided by this invention have the following technical effects:

[0195] This invention uses diphenyl as the parent nucleus, wherein an arylamine group is introduced at the 4-position (i.e., para-position) of the diphenyl to ensure that the molecule has good hole transport properties.

[0196] Furthermore, introducing another arylamine group at the 2'-position (i.e., meta-position) of the diphenyl group not only further enhances the hole transport characteristics of the molecule but also increases the steric hindrance effect to a certain extent. On the one hand, the molecule tends to form a uniform, amorphous film during the vacuum deposition process. Even under conditions where the device generates a large amount of Joule heat during long-term operation, the film is less prone to phase transition, thus improving the stability of the device. On the other hand, the molecule has a high singlet energy level, which can resist high-energy excitons from the light-emitting layer, enabling the device to achieve high efficiency.

[0197] Furthermore, when at least one of the "aryl" groups in the arylamine is selected from a naphthyl group bonded to a phenyl group at the para-position, this aryl combination not only possesses extended conjugation, but the terminal naphthyl group also provides a larger conjugated plane and electron-withdrawing effect. This not only further enhances the hole migration properties of the molecule, but more importantly, when the molecule is attacked by electrons from the luminescent layer and becomes negatively charged, the extended conjugation can effectively separate the domain charge, improving stability in the negatively charged state. This is highly advantageous for the application of electron-blocking layer materials. When at least one of the "aryl" groups in the arylamine is selected from a naphthyl group, it synergistically works with the aforementioned naphthyl group bonded to a phenyl group at the para-position to extend molecular conjugation and enhance the stability of the molecule in the negatively charged state.

[0198] Referring to Table 4, compared with the compounds provided by the present invention, the arylamine group of the comparative compound C1 is located at the 3'-position (meta) of the central biphenyl group, which weakens the steric hindrance effect, reduces the singlet energy level of the molecule, and reduces the disorder of the film formation, resulting in a significant reduction in both efficiency and lifetime in the device.

[0199] Referring to Table 4, the two aryl groups in the arylamine group of the comparative compound C2 are selected from naphthyl groups instead of phenyl-para-bonded naphthyl groups. Compared with the compound provided by the present invention, its conjugation extension is lower, which is not conducive to the stability of the molecule in a negative charge state. It also affects the charge carrier transport characteristics of the molecule. In the device, this manifests as a slight increase in voltage, and a decrease in efficiency and lifetime to varying degrees.

[0200] Referring to Table 4, in the comparative compound C3, only one aryl amino group contains a naphthyl group. Although the other two aryl groups are selected from diphenyl groups, compared to the compound provided by this invention which contains a naphthyl group bonded to an arylphenyl group at the para-position, it has fewer terminal electron-withdrawing groups. Similarly, this is detrimental to the stability of the molecule in a negatively charged state, which mainly manifests as a reduction in lifetime in devices.

[0201] In summary, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0202] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A bis(triarylamine) compound having the structure shown in formula (a): in, Ar1 to Ar4 may be the same as or different from each other, and each is independently selected from aryl groups with 6 to 22 substituted or unsubstituted carbon atoms and heteroaryl groups with 3 to 30 substituted or unsubstituted carbon atoms, and satisfies the condition that at least one of Ar1 to Ar4 is selected from the group described in formula (b1), and at least one is selected from the group described in formula (b2). m, n, r are each independently selected from integers between 0 and 4; p and q are each independently selected from integers between 0 and 7; Each of R1 to R5 may be the same or different from each other, and each is independently selected from deuterium, phenyl, or naphthyl.

2. The bis(triarylamine) compound according to claim 1, characterized in that, The bistriarylamine compounds are selected from any one of the following structures: In this context, Ar1~Ar4, m,n,r,p,q,R1~R5 represent the same meanings as in claim 1.

3. The bis(triarylamine) compound according to claim 1, characterized in that, Ar1 to Ar4 are each independently selected from aryl groups with 6 to 20 substituted or unsubstituted carbon atoms, and heteroaryl groups with 3 to 20 substituted or unsubstituted carbon atoms; optionally, Ar1 to Ar4 are each independently selected from aryl groups with 6 to 18 substituted or unsubstituted carbon atoms, and heteroaryl groups with 3 to 18 substituted or unsubstituted carbon atoms; further optionally, Ar1 to Ar4 are each independently selected from aryl groups with 6 to 16 substituted or unsubstituted carbon atoms, and heteroaryl groups with 3 to 16 substituted or unsubstituted carbon atoms.

4. A bis(triarylamine) compound according to claim 1, characterized in that, Ar1 to Ar4 are each independently selected from the following groups, whether substituted or unsubstituted: phenyl, diphenyl, naphthyl, phenanthrene, dibenzothiophene, dibenzofuran, benzonaphthothiophene, and benzonaphthofuran.

5. The bis(triarylamine) compound according to any one of claims 1, 3-4, characterized in that, The substituents in "substituted or unsubstituted" are selected from deuterium, aryl groups having 6 to 20 carbon atoms, and heteroaryl groups having 3 to 20 carbon atoms.

6. The bis(triarylamine) compound according to claim 5, characterized in that, The substituents in "substituted or unsubstituted" are selected from deuterium, phenyl, naphthyl, phenanthrene, dibenzothiophene, dibenzofuran, benzonaphthothiophene, and benzonaphthofuran.

7. The bis(triarylamine) compound according to claim 1, characterized in that, The bistriarylamine compounds are selected from any one of the following compounds:

8. A functional layer comprising a bis(triarylamine) compound according to any one of claims 1 to 7.

9. The use of the bis(triarylamine) compound as described in any one of claims 1 to 7 and / or the functional layer as described in claim 8 in organic electroluminescent devices.

10. An organic electroluminescent device, comprising a first electrode, a second electrode, and a functional layer as described in claim 8, wherein, The functional layer is at least one of the following: hole injection layer, hole transport layer, electron blocking layer, light emission layer, electron injection layer, or electron transport layer.

11. A display or lighting device comprising the organic electroluminescent device as claimed in claim 10.

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